Regional distribution of nitrogen fertilizer use and N-saving potential for improvement of food production and nitrogen use efficiency in China.

Background: An apparently large disparity still exists between developed and developing countries in historical trends of the amounts of nitrogen (N) fertilizers consumed, and the same situation holds true in China. The situation of either N overuse or underuse has become one of the major limiting factors in agricultural production and economic development in China. The issue of food security in N-poor regions has been given the greatest attention internationally. Balanced and appropriate use of N fertilizer for enriching soil fertility is an effective step in preventing soil degradation, ensuring food security, and further contributing to poverty alleviation and rural economic development in the N-poor regions.

Results: Based on the China Statistical Yearbook (2007), there could be scope for improvement of N use efficiency (NUE) in N-rich regions by reducing N fertilizer input to an optimal level (≤180 kg N ha(-1)), and also potential for increasing yield in the N-poor regions by further increasing N fertilizer supply (up to 116 kg N ha(-1)). For the N-rich regions, the average estimated potential of N saving and NUE increase could be about 15% and 23%, respectively, while for the N-poor regions the average estimated potential for yield increase could be 21% on a regional scale, when N input is increased by 13%.

Conclusion: The study suggests that to achieve the goals of regional yield improvement, it is necessary to readjust and optimize regional distribution of N fertilizer use between the N-poor and N-rich regions in China, in combination with other nutrient management practices.